Control device



Dec. 4, 1956 c. s. INGRAHAM CONTROL DEVICE Filed May 8, 1955 INVENTOR CHESTER s. iNGRAHAM ATTORNEY United States Patent coNrRoL DEVICE Chester 5. lngraham, East Aurora, N. Y., assignor to Sylvania Electric Products Inc., a corporation of Massachusetts Application May 8, 1953, Serial No. 353,728

Claims. (Cl. 20155) This invention relates to a control device involving a potentiometer, a switch and a control shaft passing through the potentiometer and switch to operate other instrumentalities such as a variable tuning condenser, permeability tuner, or a second potentiometer.

Prior art devices of this character have been bulky and complex because the through shaft requires the switch of the combination to be offset from the shaft axis. This invention, by reason of the novel switch construction and by reason of the configuration of the switch structure relative to the remaining portions of the control device overcomes these objections of the prior art constructions.

It is therefore an object of this invention to make a small compact unit having the three functions of operating a switch, operating a potentiometer and operating a third device.

It is a further object of this invention to provide a switch whose parts shall surround a substantially central control shaft.

It is a still further object of this invention to provide a combined potentiometer and switch mechanism of which parts of each shall surround a substantially central control shaft.

Yet another object of this invention is to provide a novel switch that is especially adapted for use with an operating shaft for other instrumentalities, the shaft passing through the switch in a compact arrangement of switch and shaft.

Other objects can be ascertained after reading the following specification and claims when read in conjunction with the accompanying drawings in which Fig. l is a longitudinal cross-section through a combined potentiometer, switch and control shaft, the control shaft being shown in side elevation.

Fig. 2 is a rear view of the combined unit showing the switch arrangement, and

Fig. 3 is an exploded view of the unit showing its component parts in perspective.

Referring to the figures more in detail, there is illustrated a housing comprised of an oval back plate 10, a wall 12, oval in cross-section, secured to the back plate, a cylindrical wall 14 secured to the first wall 12 and an insulating front plate 16 engaged by said cylindrical wall. A slotted partition plate 18 which may be made integral with the wall 12 forms two chambers in the unit, one to house the potentiometer and the other to house the switch. The back plate, the front plate and the partition wall are all centrally apertured to receive an operating shaft 2% for a third instrumentality, as will be described more in detail hereinafter. a I

The cylindrical wall may be secured to the oval wall 12 by spot welding or other well known means. The back plate 16 is secured to the oval wall 12 by means of lugs 22 extending from the edge of the wall and bent around the back of plate 10, some of the lugs lying in recessed portions 24- of the back plate to prevent sliding of the plate on the edge of the wall and others of the 2,773,157 Patented Dec. 4, 1956 ice lugs passing through holes 26 in the back plate.

externally threaded bushing 32, adapted to pass through.

a mounting hole in a chassis wall and adapted to have a lock nut threaded thereon to secure the unit in place.. The plate 16 is generally circular in plan but there is an. arcuate extension providing four tooth portions 34 with;

three intermediate recesses to snugly accommodate potentiometer terminal members 36. The outside terminal. members are respectively connected to two opposite ends of an interrupted annular disc 33 having a carbon resistor surface, the disc and terminal members being secured to the insulating plate 16 by rivets 40 or the like- Cooperating with the resistance coated disc is a rotatable contact plate 42 having, for the sake of securing better electrical contact with the disc, a pair of spring fingers 44 engaging the resistance face of the disc 38. The circuit is completed to the middle terminal 36 of the potentiometer, secured to the insulating plate by a rivet, by means of a stationary contact ring 46 in sliding contact with the plate 42 and conveniently formed of stiff spring wire surrounding a flange 47 on the plate 42, this contact ring having a terminal portion 48 electrically joined to the middle terminal 36. The contact ring 46 and the rotatable plate 42 surround in noncontacting relation a hollow potentiometer and switch drive shaft 51} by reason of construction later described. Mounted against a collar on the shaft, as shown in Fig. l, is a metallic thrust ring 52 and interposed between the thrust ring and the stationary contact ring 46 is an insulating washer 54 against which the contact ring 46 and flange 47 bear. The inner end of the shaft 50, that is the end within the housing, is provided with a bifurcated end 56 and mounted on this end is a switch control arm 60 with irregularly shaped hole 62 to receive the ends 56 in driving relationship (see Fig. 1) so as to cause the arm to rotate with the shaft 50. interposed between the rotatable contact plate 42 and the arm 60 is an insulating washer 64 and to transfer motion from the arm 60 to the rotatable contact plate, a nib or pin 66 is provided on the arm engaging in a slot 68 in the washer 64. Furthermore, thewasher 6 2' is provided with slotted portions 7% engageable by lugs 72 extending at right angles to the contact plate 42. Between the washer 64 and the plate 42 is a somewhat elliptical insulating washer contoured to permit springing of the contacts 44 in a direction away from the resistor 38. This construction, amongst other functions, provides for maintaining the plate 42 out of contact with the shaft 54). To hold the several elements on the shaft together there is provided a cup shaped member 74 having an irregular hole 76 conforming in shape to the hole 62 in the arm 64 the bifurcations of the end 56 of the shaft being bent over the base of the cup to confine the washer 54, wire ring 46, contact plate 42. washers 65 and 64- and switch arm 61) between the thrust ring 52 and the cup shaped member, as shown in Fig. l. The edge of the wall of the cup shaped member forms a thrust member engageable with the partition wall 13 should the shaft 54) be thrust inwardly of the housing.

Theswitch control arm 6% has a switch operating lug 7S and a control arm stop finger 89. The stop finger engages an abutment 82 on the wall 12 while the switch operating lug 73 is in position to engage one or the other of the two parallel spaced arms 84 of a pivoted spring stressing and spring end displacing crank arm 86. The. crank arm 86 is pivoted on a pin 88 provided with a spacing washer89, the pin being fastened at one end in an apertured portion 90 of the back plate 10 and.

Similarly the front plate 16 is secured to the edge of cylin-' drical wall 14 by means of lugs 28 bent around the front having its other end resting in a hole 91 in an extension of the partition wall. The partition wall is furthermore arcuately slotted as shown at 92 to enable the arms $54 to project into the housing portion in which the lug '78 operates and to be engaged by said lug in the rotation of the arm so. The crank arm is conveniently formed of a single sheet of blank material bent to form the arms 84 and a saddle with slotted portion 93, shown in dotted lines in Fig. 3, and with a reentrant slot 94. Retained by the slotted portion and the reentrant slot is a fiber block 95, the upper edge of which has a cen tral tongue 95 which, as shown in Fig. 2, pivotally engages with the lower end of a C-shaped spring 97 made of fiat stock and stressed to its arcuate form by entering into a rectangular slot 98 in the lower end of the spring. The upper end of the spring is provided with a slot see similar in shape to the slot 98, pivotally engaging a tongue MP2 of a spring leaf liiid, said leaf spring carrying a contact member we. The leaf spring is further provided with a right angularly bent portion adapted to be fastened, as by a rivet liltl, to an angularly bent saddle 112 in turn fastened to the back plate ll) by a rivet ill- E- passing through a hole 116 in the back plate. The saddle also has an abutment finger 118 positioned in the path of movement of the leaf spring to prevent the lower end of the spring leaf from being driven too far to the right, as seen in Fig. 2, and thereby to prevent possible disengagement of the C-shaped spring @7 from the leaf spring 104. The back plate also has mounted on it a fixed contact i2 3: mounted on an angular bracket 122 and fastened in position on the plate Ill by a rivet 124 passing through a hole 126 in the plate. The leaf spring is biased to normally urge the contacts 106 and 12% into engagement. The bracket 122 has a backwardly extending short finger l2? fitting in a hole 130 in the back plate to prevent rotation of the contact and, in the lower left hand side of the vertical flange of the saddle 112 there is provided with a backwardiy extending finger to engage in a hole 132 in the plate ill to prevent rotation of the saddle. The rivets 114 and 124 also serve to mount a pair of switch terminals 134 on the back plate, these too being provided with short fingers to engage in the holes 139 and 132 of the plate ill to prevent rotation thereof.

From the above description it will be clear that operation of the hollow shaft 51 will rotate the plate so via the bifurcations so on the shaft thereby causing the lug "It; on the plate to engage one of the arms 84 on the crank arm 86 and through the fiber block 95 and C-shaped spring l operate the spring leaf lit-. Also the rotation of the plate oil) will cause its projection he to rotate the washer 64 and through it the contact plate 42 with its fingers operating over the resistor A the same time without interfering with the operation of the switch or potentiometer, the through shaft 2t? may be operated to control another element.

This shaft extends centrally through the entire organization thus far described and 011 to some instrumentality mounted in the chassis or on back of the control unit to be operated by the shaft. The instrumentality, as pointed out heretofore, may be a tuner of some character such as a tuner having an adjustable condenser or ad justable permeable member or it may be another potentiometer. The front ends of the control shaft Sill and of the operating shaft 2t) may have nested or superimposed operating knobs mounted thereon to provide ready means for operating all of the units controlled by the shafts. The shaft Ztl, it will be noted, passes through the hollow shaft Sll as well as past the inner area of the C-shaped spring f7. The spring is so shaped and so mounted that in its movement it never contacts the shaft 20 and yet it serves to transmit forces from crank arm 36 to the leaf spring by reason of the connections at 98 and 100. The forces are carried around the shaft 20. The virtual line of thrust is, however, through the shaft Eli and it shifts from a position in which the switch contacts are closed by reason mainly of spring leaf bias, to one overcoming the bias of the spring so as to effect separation of the contacts. As the block is rotated the spring is first compressed by reason of points 96 and 1692 being brought closer together and then released from pressure to allow parts to snap to their final positions. This method of transmitting forces around the shaft is effective in moving the movable contact and yet permits compact arrangement of parts not only as to the switch itself but as to the combination of switch and potentiometer.

l t will be obvious that various details of the organization may be varied without departing from the spirit of my invention, as defined in the following claims.

What is claimed is:

1. A control device including a casing having at least two parallel walls with alined apertures, a shaft traversing said casing and passing through the alined apertures, a pair of contacts within said casing one of which is movable and mounted on a leaf spring extending toward the shaft, an operating member in said casing, said pair of contacts and operating member being diametrically positioned with respect to said shaft, and means including a bowed force transmitting member partially encompassing the shaft and interconnecting the movable contact with the operating member.

2. A control device including a casing having at least two parallel walls with alined apertures in said walls, a shaft traversing said casing and passing through the alined apertures, a pair of cooperating contacts within said casing one of which is mounted on a fiat leaf having a free end extending toward the shaft, an operating means for said leaf including a pivoted member, the free end of which extends toward said shaft, said flat leaf and pivoted member being on substantially diametrically opposite sides of the shaft, and a bow shaped spring member pivotally connected to both the free end of the flat leaf and the free end of the pivoted member and partially encompassing the shaft.

3. A control device comprising a casing structure having parallel front and back walls and a parallel partition wall dividing the casing into two chambers, potentiometer in one of the chambers and a switch comprising contacts and operating means therefor in the other, means for operating said potentiometer and switch comprising in part a hollow shaft extending through the front wall and terminating short of the partition wall, the partition wall and back wall being provided with apertures in alincment with the hollow shaft, a control shaft extending through. the hollow shaft, ootentiometer chamber, and switch chamber and through the aligned apertures, the switch contacts lying to one side of the control shaft, displaceable means for operating the contacts on a diametrically opposite side of the shaft, and bowed force transmitting means interconnecting the displaceable means and one of the contacts to transmit motion from the former to the latter.

4. A control device including a casing having at least two parallel walls with aligned apertures through which an operating shaft may be passed, a pair of contacts within the casing to one side of the aligned apertures, a cantilever leaf spring mounting one of said contacts, with the free end of the spring extending toward the axis of the aligned apertures but terminating short of the apertures, an operating member in the casing on the other side of the axis of the apertures, a bowed force transmitting member bowed around the apertures to avoid passing across the openings and interconnecti2.1g the free end of the leaf spring with the operating member, and means coaxial with said apertures and extending through one of them to control the movement of said operating member.

5. A control device comprising a casing structure having parallel front and back walls and a parallel portion 5 wall dividing the casing into two chambers, a potentiometer in one of the chambers and a switch comprising contacts and operating means therefor in the other, means for operating said potentiometer and switch comprising in part a hollow shaft extending through the front wall and terminating short of the partition wall, the partition wall and back wall being provided with apertures in alignment with the hollow shaft, said apertures being provided to accommodate a central shaft adapted also to extend through the hollow shaft, potentiometer chamber and 6 connecting the displaceable means and one of the contacts to transmit motion from the former to the latter.

References Cited in the file of this patent UNITED STATES PATENTS 2,072,240 Zigler Mar. 2, 1937 2,159,369 Draving et al. May 23, 1939 2,211,706 Schellenger Aug. 13, 1940 2,237,705 Kohl Apr. 8, 1941 2,510,021 Kaminky May 30, 1950 2,650,270 Mucher Aug. 25, 1953 FOREIGN PATENTS 838,712 France Dec. 16, 1938 

